PREA (Personalized Recommendation Algorithms Toolkit) is an open source Java software that provides easy comparison of collaborative filtering algorithms. With increase demand of personalized services in e-commerce, recommendation systems are playing a critical role in commercial websites. In academia, many researchers have tried to achieve better performance and accuracy with various algorithms. Netflix Prize, held from 2006 to 2009, also contributed to take attention to research in collaborative filtering and recommendation systems. Our software provides a unique interface to compare several representative recommendation algorithms with common datasets as well as with your own dataset.